This invention relates to valves, and more particularly to shuttle valves. The invention is an improvement upon shuttle valves of the type made and sold by applicant's assignee illustrated in the leaflet entitled: "Hydraulic Shuttle Valves, Specification Sheet Number 103, Gilmore Valve Company", the disclosure of which is incorporated herein by reference to show typical dimensions. See especially the 11/2" Shuttle Valve, Assembly Part No. 10-50003 (Drawing No. 22404). See also U.S. Pat. No. 3,533,431-Kuenzel and Gilmore, assigned to applicant's assignee, for another improvement in such valves.
Such shuttle valves may be employed in connection with underwater oil field equipment. For example, the lower ends of two hydraulic fluid accumulators (tanks with air space in the top) may be tied to the inlets of a shuttle valve. Each of two high pressure flow lines feeding the accumulators may be connected thereto between the shuttle valve and one of the tanks. The outlet of the shuttle valve will supply fluid from whichever one of the flow lines has the higher pressure.
It is especially important that underwater shuttle valves have a long trouble-free life because of their inaccessability. Due to the high working pressures, up to several thousand (e.g. 5000) psi, the possible differential pressure on such shuttle valves is very high. Sometimes the resulting high momentum of a shuttle as it moves from one seat to another creates enough impact to break or crack the cage or cause it to be warped, thus disrupting proper valve operation.